Earthquake: The Long Road Back : Worst May Come for Motorists on Monday : Traffic: Rain and more normal workday volume may add up to greater congestion. Riordan is expected to announce contingency plans today, including possibly converting some streets to one-way thoroughfares.

As awful as traffic has been since the earthquake, transportation officials said Friday that commuters had better brace for congestion to get worse next week.

The crippled freeways and jammed side streets will be filled with more people returning to their jobs.

"Many people did not attempt to get to work after the earthquake," said Frank White, chief of the Los Angeles County Metropolitan Transportation Authority. "But on Monday--we are all afraid of what we will face."

In an effort to ease what could be monumental traffic jams, Mayor Richard Riordan intends to announce a plan today to relieve congestion on city streets. Riordan is considering converting some east-west streets, such as Pico and Olympic boulevards, into one-way thoroughfares, Deputy Mayor Rae James said.

Meanwhile, transportation officials are preparing for a worst-case scenario: rain along with the typical workday volume of commuters on the region's freeway network, which suffered damage on six roadways--including the Golden State, Antelope Valley and Simi Valley freeways.

Alternate routes along surface streets can handle only 60% of the traffic diverted from broken freeways, said Robert R. Yates, general manager of the Los Angeles Department of Transportation.

Do not drive alone, Yates and others urged. Take public transit or car-pool.

The key choke points, transportation officials say, are at the downed portion of the Santa Monica Freeway--usually traversed by about 340,000 motorists daily--and the main arteries into the Santa Clarita Valley, which typically carried more than 200,000 vehicles daily.

In the days since the 6.6-magnitude earthquake, transportation officials have struggled to increase options for beleaguered commuters. Workers have scurried to clear the debris from freeways, removing nearly 5,000 yards of concrete and steel rubble from the collapsed Interstate 5 and Antelope Valley Freeway. Engineers frantically analyzed detour routes. Transit planners mapped out new stations for commuter trains.

Starting Monday, the Santa Clarita Metrolink commuter train will extend its route 50 miles, using freight tracks, to include station stops in Palmdale and Lancaster. A station at Vincent on that route will open Jan. 31. A fourth station, in Canyon Country at Via Princessa, is expected to open Feb. 7. For the rest of the month, Metrolink officials say they will honor Antelope Valley Transit passes and tickets.

White said the agency also plans to open another new route, with stations in Northridge and Camarillo in February. Sites for those two stations have not been selected. Some of the new stations are expected to be rudimentary, with gravel lots for parking and a wooden platform. "But I am quite sure commuters will be pleased with even that," White said.

To ease the flow of motorists from north county communities, Caltrans has worked to shorten detours along the Golden State Freeway. Jerry Baxter, head of the Caltrans district office, said crews hoped to open an alternate route Tuesday that would utilize The Old Road near Weldon Canyon Road to Calgrove Boulevard in Santa Clarita.

This route would allow two lanes of traffic in each direction, Baxter said. In the days ahead, officials will decide whether to convert the newly opened lanes on the Golden State to car-pool lanes.

With inspection reports arriving continually, Caltrans officials said the status of roads can quickly change. On Friday afternoon, officials closed connectors between the westbound Ventura Freeway to the southbound and northbound Glendale Freeway. They also shut the connector between the eastbound Ventura to the southbound Glendale Freeway. The interchange is expected to remain closed for two days.

"Anytime we have to close something else, it's not good news," said Caltrans spokesman Russ Snyder, who added that it was not known whether those newly closed interchanges, which need shoring up, were damaged in Monday's quake or the aftershocks.

To help Westside commuters who use the Santa Monica Freeway, the MTA has started a new bus line and will deploy 20 additional buses to five routes: Lines 2, 4, 20-320, 439 and 454. The new Westside Special bus, which started service Thursday, begins at the westernmost part of its route, at Pacific Coast Highway and Temescal Canyon Road near Will Rogers State Beach.

Meanwhile, Los Angeles officials tried to fix traffic lights, which have impeded traffic flow, predominantly on the Westside. Most of the 6,400 miles of city streets were virtually untouched by the earthquake, except in areas along the Santa Monica Freeway where debris showered down upon thoroughfares. But 38 traffic signals--including 26 that were affected by the downed Santa Monica Freeway--have stopped working.